|I looked at your previous thread lurkswithin pointed to.|
ATX moards are always powered in some places even when the computer is not running, as long as live AC power is being supplied to the case and the power supply.
You MUST disconnect the AC power to your case / power supply whenever you change any connection inside your case or plug in or unplug ram or a card in a slot, otherwise you can easily ruin something!
This is especially important for AGP and PCI-E cards!
Your 9800 card is 4X/8X only, it cannot support 2X, so it should get along fine with the 845's chipset and AGP support.It sounds like you have the additional power plugged into the card socket so that's okay.
You've got a lot more than enough PS capacity.
I have been told by pros at a place that builds custom systems all the time you don't ever need more than 350 watts PS capacity if your mboard has no PCI-E slots, unless the computer is a heavily loaded server.
If your system is working fine other wise, spinning the hard drive normally, and the HDD led is blinking normally as if it's loading Windows normally, assuming the card is not defective and you haven't damaged it, I think I know how to fix your problem(s).
A few things first....
Your AGP card often will not work properly if the main chipset drivers have not been loaded!
Whenever you load Windows from a regular Windows CD (or DVD) from scratch, after Setup is finished you must load the drivers for the mboard, particularly the main chipset drivers, in order for Windows to have the proper drivers for and information about your mboard hardware, including it's AGP or PCI-E, ACPI, and hard drive controller support. If you have a generic system and have the CD that came with the mboard, all the necessary drivers are on it. If you load drivers from the web, brand name system builders and mboard makers often DO NOT have the main chipset drivers listed in the downloads for your model - in that case you must go to the maker of the main chipset's web site, get the drivers, and load them.
In this case, if you don't see the main chipset drivers for the 845 chipset where the downlods for your mboard are, get them from the Intel web site and load them!
You do not have to disable your onboard video in Device Manager - almost always, installing a video card in your AGP slot (or PCI slot) will disable it automatically.
You are supposed to un-install any video drivers and associated programs you have already installed that you find in Add/Remove Programs BEFORE you install a card in the AGP slot )or PCI slot), but usually you can do that afterwards instead, AND/OR in any case you are supposed to Un-install (not disable) the onboard Display Adapter listing in Device Manager BEFORE you Shut Down Windows to install the AGP card, to set Windows to a default VGA mode (you will still have video after you un-install it).
Other things you may run into:
First off, your card probably has TWO monitor ports.
There are lots of video chipsets that will not work properly if a single monitor is plugged into the secondary monitor port on the card - I've seen this myself with a few ATI chipset cards.
Make sure it's plugged into the primary port on the card! See the manual for the card, or just try the other port!
You may have two DVI ports, or a VGA and a DVI port. If your monitor is DVI connected and cannot be connected to a VGA port as well (if the monitor has both you can use one OR the other), your problem may not be solvable, because if you have a VGA port it is probably the primary card port.
You can use a commonly available adapter (male DVI to female VGA) to convert a DVI port to VGA port use, but the opposite will probably not work - DVI probably requires more connections than the 15 a VGA port can provide.
Secondly, sometimes a video chipset will not detect your monitor properly and you will get no display unless the monitor is switched on at least a few seconds before you boot the computer.
Thirdly, even if both of the above are okay, sometimes the video chipset doesn't detect the monitor properly and you get no display because the video chipset doesn't know what mode to set itself too - I've seen this myself with a few ATI chipset cards.
In that case, you press F8 repeatedly while booting, don't hold down the key, and when the menu appears, choose Enable VGA mode (you will probably get no display in Safe Mode either) - that boots Windows normally except it loads only basic VGA mode drivers that all monitors and cards support.
When you get to the desktop, RIGHT click on a blank area of the screen, choose Properties, Settings, Advanced, and change the Monitor Drivers to either Plug and Play Monitor, or if you have the CD that came with the monitor, choose Have Disk and point Windows to the location of the drivers on the CD - windows is looking for an *.inf file.
Save settings, reboot normally - you should have normal video.
If you have an LCD monitor, you should always load the specific drivers for the monitor. The Plug and Play Monitor setting was not designed to support LCD displays other than those on older laptops, it has not changed since XP was first released in any XP version, and it is possible to choose settings that will damage your LCD monitor.
If none of that helps, your card is probably damaged. Try it on another computer to confirm that, keeping in mind the things I said above. If it doesn't work on another computer, if you did not disconnect the AC power to the power supply when you plugged in or unplugged this card, you may have ruined it yourself.
Your bios Setup has settings for Intialize Video first: xxx or Primary video: xxx, or similar. You will have video in Windows XP regardless of how that is set, but the AGP card will not be capable of it's superior modes when it's specific drivers have been loaded unless that is set to AGP, or card slot, or similar, NOT PCI or onboard video, or whatever.